Since the introduction of the first biologic therapy for rheumatoid arthritis just over a decade ago, 9 drugs have been approved for registration, including 5 TNF inhibitors.Their general acceptance as standard of care world-wide has established new standards for safety and effectiveness in treating rheumatic diseases.Yet in spite of distinct targets and mechanisms of action for these molecules (tumor necrosis factor, CTLA-4, CD20, IL-6), results from clinical trials have demonstrated striking similarities among them.